This invention pertains generally to hand operated shearing tools for forming a series of bent up, spaced apart, partially cut blank portions along the edge of a piece of sheet metal. Joints between various forms of sheet metal are thus provided whereby, for example, a cylindrical member can be joined to a flat sheet by a series of turned tabs or flanges which are spaced around the cylindrical member and are ultimately bent on opposite sides of the flat sheet. Such a joint is shown in the U.S. Pat. No. 3,423,984 to Keymer which issued Jan. 28, 1969 and is entitled "Take-Off Tool". The tool shown in that patent simply cuts a generally rectangular notch from the cylindrical member, leaving intervening tabs which are subsequently turned up by a pliers or the like.
Another example of the prior art is shown in the U.S. Pat. No. 1,602,169 which issued Oct. 5, 1926 to Purnell and entitled "Shearing Tool" in which alternately spaced, partially cut blanks are formed by the tool, but the partially cut blanks must then subsequently be turned or bent by swinging the tool itself through the appropriate arcuate travel, usually 90 degrees; thus two distinct motions are required with the tool to form the turned up tab; namely the first cutting action and then subsequent swinging of the entire tool, all of which results in time consuming effort and not always results in accurately and uniformly cut tabs.
Still another example of the prior art is shown in U.S. Pat. No. 812,645 which issued Feb. 13, 1906 to Gardner and entitled "Combined Punch and Shears" and in which a single slit is cut at an angle to the edge of the metal and one side of the cut is then turned slightly inwardly or laterally to permit insertion of a wire through the cleft and into an aperture.
Other forms of prior art tools of this general character and which have guides or gauges or discharge devices but which simply cut out a complete notch in the metal are shown in the U.S. Pat. Nos. 2,224,226 which issued Dec. 10, 1940 to Jensen and entitled "Industrial Cutting Tool"; U.S. Pat. No. 2,595,841 which issued May 6, 1952 to Glick et al and entitled "Hand Notching Tool"; and U.S. Pat. No. 2,751,681 which issued June 26, 1956 to Hillson and entitled "Miter Guide". cl SUMMARY OF THE INVENTION
The present invention provides a hand operated shears for forming a series of partially cut blanks from a margin of a pipe and simultaneously bending the partially cut blanks at a right angle to the pipe. The invention contemplates a hand operating shearing tool which cuts two opposed sides of the blank and simultaneously causes the intervening portion of the metal, namely the partially cut blank, to be bent at a substantially right angle to the sheet or cylinder being cut without damaging or injuring the rest of the material. As a result, a series of accurately aligned and bent partially cut blanks are provided which result in a tight joint between the parts to be joined, such as a cylinder and a flat sheet. A more specific aspect of the invention relates to such a tool having a pair of generally rectangular cutting members, the opposite sides of such members cooperating to form side cuts on the blank and the outermost cooperating edge of the two members having a clearance therebetween to permit the partially cut blank to be turned at a substantially right angle to the sheet or cylinder being cut. A more limited aspect of the invention relates to an adjustable stop means between the two movable handles of the tool whereby the amount or degree of turning of the blank can be varied. In addition, a readily adjustable depth gauge is provided to insure that the blanks are of equal depth to consequently provide a tight joint between the parts to be ultimately assembled.
The present invention also provides a pair of cooperable and interengaging cutting members of the above type which can be used as replacement dies for conventional cutting or notching tools.
These and other objects and advantages of the present invention will appear hereinafter as this disclosure progresses, reference being had to the accompanying drawings.